Once again, it’s research time. Simple things like having one of my soldiers come home on leave. Let it not be said, I fail to research! “In the British Army, for example, soldiers were allowed a leave every fifteen months on average, while officers were allowed one every three months.”
Starting in 1915, periods of leave known as “permissionnaires” played a vital role in supporting the morale of troops, allowing fighters to rest, and letting some families come together. These periods showed the limits to the endurance of soldiers, as well as the strength of ties between civilians and combatants, which translated to social cohesion during and after the First World War.
Source: Soldiers on Leave | International Encyclopedia of the First World War (WW1)